diff --git a/admin/tool/task/run_adhoctasks.php b/admin/tool/task/run_adhoctasks.php
index 81a68d4535b..b1b831c3368 100644
--- a/admin/tool/task/run_adhoctasks.php
+++ b/admin/tool/task/run_adhoctasks.php
@@ -117,7 +117,7 @@ require_sesskey();
 \core\session\manager::write_close();
 
 // Prepare to handle output via mtrace.
-require('lib.php');
+require_once("{$CFG->dirroot}/{$CFG->admin}/tool/task/lib.php");
 $CFG->mtrace_wrapper = 'tool_task_mtrace_wrapper';
 
 // Run the specified tasks.
diff --git a/admin/tool/task/schedule_task.php b/admin/tool/task/schedule_task.php
index bdd02bfb693..654a411f5a0 100644
--- a/admin/tool/task/schedule_task.php
+++ b/admin/tool/task/schedule_task.php
@@ -89,7 +89,8 @@ echo $OUTPUT->select_element_for_append();
 
 // Prepare to handle output via mtrace.
 echo html_writer::start_tag('pre', ['style' => 'color: #fff; background: #333; padding: 1em; min-height: 24lh']);
-require('lib.php');
+
+require_once("{$CFG->dirroot}/{$CFG->admin}/tool/task/lib.php");
 $CFG->mtrace_wrapper = 'tool_task_mtrace_wrapper';
 
 // Run the specified task (this will output an error if it doesn't exist).